Growth and optical properties of hierarchical flower-like ZnO nanostructures

The integration of low dimensions nanoscale building blocks into 3D architectures has attracted great scientific attention. We have obtained the novel hierarchical flower-like ZnO nanostructures self-assembled by nanorods via a facile hydrothermal method. The as-synthesized samples were characterized with various technologies. The field emission scanning electron microscope (FESEM) images indicated that hydroxide ions play a significant role on the formation of hierarchical flower-like ZnO nanostructures. The X-ray diffraction (XRD) result proved that the nanocrystals were well crystallized hexagonal wurtzite structure. A possible growth mechanism of the nanostructures was proposed based on the effects of hydroxide ions. And the TEM imagines provided some important evidence for the proposed growth mechanism. UV-vis adsorption and photoluminescence (PL) spectra results indicated that the obtained ZnO nanostructurs have a good optical-absorption and photoluminescence property. The as-synthesized ZnO nanostructures exhibited superior photocatalytic performance, which was higher than that of commercially available ZnO.